IBM eServer zSeries 900 Technical Guide

Chapter 3. Connectivity 79

򐂰 The assignment information can be exported and imported.

򐂰 The channel port is identified by its location.

򐂰 The CHPID Assignment task is an IBM service representative-only function.

򐂰 When a service support representative is performing a remap of the CHPID assignments,

the following checking takes place:

– Only physical channels installed and configured can be assigned CHPID numbers.

• One exception is if a channel was installed and failed such that it cannot be

detected.

• Another exception is a definition error or “installed-reserved” when the CHPID is not

defined.

– Only channel ports in manual reserved (off-line to the operating system) state can have

their CHPIDs changed/reassigned.

– If POR is complete and ICP or IQD CHPIDs are defined, those CHPID numbers will not

be available for assignment.

򐂰 PCICC and PCICA features consume CHPID numbers.

Fixing CHPID assignment mismatches on upgrades

If, for any reason, the default CHPID assignment performed during an upgrade does not

match your expectations, and if you already defined and activated your own I/O configuration

(CHPIDs, control units, I/O devices), then an IBM Service Representative can manually

remap CHPID numbers to your choice. Once the CHPIDs have been remapped, they can be

configured online and used.

Changing CHPID assignments

If you want to change CHPID assignments for a defined, activated and used CHPID and use

the corresponding channel port for another, not already assigned, CHPID, the IBM Service

Representative must put the defined and activated CHPID in the reserved state in order to be

able to remap it. Once the remapping has been performed, you can define and activate the

new CHPID. You can then configure it online.

3.1.4 HiperSockets (iQDIO) and Internal Coupling-3 (IC-3) channel definitions

Internal Coupling-3 (IC-3) channels and HiperSockets (iQDIO) are virtual attachments and,

as such, require no real hardware. However, they do require CHPID numbers and they do

need to be defined in the IOCDS.

They are not assigned to CHPIDs during the default channel CHPID assignment. iQDIO and

IC-3 CHPID assignments must be performed using the Hardware Configuration Dialog (HCD)

or the I/O Configuration Program (IOCP).

The CHPID type for IC-3 channels is ICP, and the CHPID type for HiperSockets is IQD. IBM

recommends you choose the CHPID numbers wisely:

򐂰 Use CHPID numbers from the high range (that is, FF) and work down. This is because the

default CHPID numbers assigned to new I/O features that you may add in the future will

always be assigned from the low CHPID numbers working up.

򐂰 It is suggested that you define a minimum of (ICP) CHPIDs for Internal Coupling. For most

customers, IBM suggests defining just one ICP for each coupling facility (CF) logical

partition (LP) in your configuration. For instance, if your general purpose configuration is

several operating system LPs and one CF LP, you would define one pair of connected ICP

CHPIDs shared by all the LPs in your configuration. If your configuration is several

operating system LPs and two CF LPs, you still would define one connected pair of ICP

CHPIDs, but one ICP should be defined as shared by the operating system images and